I need to build a Cage, Tech Info Needed. John Coffey?

[hoov100]

everyone that see's my hoop says its too far up and i should have it sit back 1-2 inches from the dome light thingy. i sit up closer to the steering wheel and if i put the hoop in the lower roof area and further back away from my head area. i didn't like the idea of the hoop a whole foot back away from my head if there was to be an accident and leaving plenty of area for the roof to cave in where my head actually sits.

 

I wouldn't be worried about that, as much as I would be, about how far away the hoop is from the door. A roll bar i intended to prevent things from hitting the occupants in the event of a crash and to prevent the car from collapsing in on the driver. The main hoop can't protect you very well, if you're shoulders/body stick out past it.

 

[hoov100]

Whoops, double post...

Edited April 25, 2010 by hoov100

[piston]

yep!!! my shoulders and arms sit right along the line if any a bit more inwards. 1 1/2 inch gap in the pic above. i doubt another inch outward will make that big of a difference.

[hoov100]

yep!!! my shoulders and arms sit right along the line if any a bit more inwards. 1 1/2 inch gap in the pic above. i doubt another inch outward will make that big of a difference.

 

It could mean the difference between life or death. Imagine a 5000 pound SUV hitting that main hoop dead on or just to the left, if something hits it, it's most likely going deform around it by about at least 6 inches depending on speed. Now who is sitting right in that spot? most likely you, or someone you care about is driving. what is going to happen when you're legs are pinched against the trans tunnel and the car is still pushing you're upper torso into the passenger side of the car? what if you're daughter/wife/GF/sister/brother...etc is sitting in the passenger seat and it gets hit on the passenger side? what if you get rear ended hard enough in traffic, to the point where you are pinched between two cars and the rear car crushes the chassis enough to push the cage forward and crush you? You're seriously neglecting you're own personal safety and the safety of anyone riding in the car with that mentality.

[johnc]

everyone that see's my hoop says its too far up and i should have it sit back 1-2 inches from the dome light thingy. i sit up closer to the steering wheel and if i put the hoop in the lower roof area and further back away from my head area. i didn't like the idea of the hoop a whole foot back away from my head if there was to be an accident and leaving plenty of area for the roof to cave in where my head actually sits.

 

OK. The main hoop needs to be no more then 6" behind the driver's helmet with the driver in a normal, seated position and completely strapped in.

[johnc]

It could mean the difference between life or death. Imagine a 5000 pound SUV hitting that main hoop dead on or just to the left, if something hits it, it's most likely going deform around it by about at least 6 inches depending on speed. Now who is sitting right in that spot? most likely you, or someone you care about is driving. what is going to happen when you're legs are pinched against the trans tunnel and the car is still pushing you're upper torso into the passenger side of the car? what if you're daughter/wife/GF/sister/brother...etc is sitting in the passenger seat and it gets hit on the passenger side? what if you get rear ended hard enough in traffic, to the point where you are pinched between two cars and the rear car crushes the chassis enough to push the cage forward and crush you? You're seriously neglecting you're own personal safety and the safety of anyone riding in the car with that mentality.

 

Well... maybe. That gap between the main hoop and the side of the car is not significant in the type of impact you're describing above. Also, the main hoop in a roll bar/cage is designed to protect in a rollover, not side impact. The majority of whatever protection the car can provide will be done by the rocker panel, door assembly, and roof structure. In the type of impact described above you actually want the driver/passenger seat to move inward and have the trans tunnel collapse. New cars even have things called "pushers" designed into the floor pan, rocker panel, and seat mounts to move the entire seat mounting structure inward in a side impact. Trans mounts are also designed to break, forcing the transmission down to give a little more room for the seats to move inward.

 

Roll cage design is very slowly moving away from a totally rigid structure at the outer extremities of the chassis. That type of design imparts too much force too quickly on the occupants. Crush zones are now recognized as important parts of driver protection.

[piston]

thanks john. i knew somewhere i saw the six inch gap rule in one of your nhra rules. im short, thats why mine is 2" more forward compare to others. everyone views it from their point of sitting down but they dont think about the short ass owner(me). lol.

 

hoov100, im not trying to be a smart ass but your a bit over reacting over this ROLL cage for side impact reasons. the ROLL cage is for unexpected ROLL over's. in case you ROLL over, it helps keep the top from caving in. not if someone hits you from the side with a suv. the chances of a suv jumping out the side of a race track is 1 in a million. if anyone t-bones you in a z at high speeds on regular belts, i dont care what you say, your head is bashing through the side windows. again, that is what door bars are for. think about an off road jeep or truck. the hoop is there to protect the roof from fully caving in, but the roll bar/cage sits really crappy. again, the cheapo JEGS cage is NHRA approve if weld to their specs. im 5.6" 160 pounds, that gives me a better chance compare to the other 80% of bigger/taller guys using the same cage.